Electronic transmission lines which are able to operate at frequencies of the order of 50 GHz require careful design in order to ensure efficient operation, specifically to reduce unwanted energy reflections and/or absorptions. Moreover, interconnecting these lines without careful design of the interconnections may lead to further similar inefficiencies of operation. Types of lines which are used to propagate these frequencies include coaxial and printed circuit (PC) transmission lines.
In the specification and in the claims, a PC transmission line is assumed to be any transmission line formed on a printed circuit board which is able to propagate frequencies in a range from DC (0 Hz) to approximately 50 GHz. Typically, a PC transmission line comprises a “signal” strip separated and insulated from at least one ground strip and/or ground plane. PC transmission lines are well known in the electronics art, and may be termed, inter alia, microstrip, stripline, stripguide, coplanar waveguide (CPW), grounded coplanar waveguide (GCPW), and/or WEN line(s).
Corning Gilbert Inc., of Glendale, Ariz., produce a Gilbert Puny Push On (GPPO) edge mount, catalog series number B010-L, and a GPPO right angle to printed circuit board coupling, catalog series number B009-P, both of which are designed to couple a PC transmission line to a coaxial transmission line. In both cases, the component is connected to the PC transmission line, and the combined component and transmission line may then be “pushed-on” to the coaxial transmission line so that the two lines are interconnected.
In many cases, a component having a coaxial transmission line output is adjusted to optimize performance of the component, and/or has measurements made on the component, before the component is ready for final use. Typically, a connector is attached to the output, enabling a standard coaxial connector to be coupled to the component's output. After the adjustments and/or measurements have been made, the connector is removed and the component is available for final use as a “drop-in” component.
U.S. Pat. No. 3,539,966, to Logan, whose disclosure is incorporated herein by reference, describes a PC transmission line to coaxial line connector which can be attached to a printed circuit board. A coaxial line adapter is soldered in place on the board, and an outer shell assembly is clamped over the adapter and is held in place by screws.
Couplings for connecting transmission lines operating at frequencies of 50 GHz and above need to pay particular attention to surface currents flowing on the grounds, in order to operate efficiently. In order to maintain a good ground regime, i.e., proper alignment of ground paths, differences between electrical properties (e.g., inductance and resistance differences) of incident and return currents must be minimized.